1. Field of the Invention
The present invention relates generally to a tool and method for extracting a high pin count electronic package or similar electronic module from a socket which engages the pins of the package with friction force. More particularly, it relates to such a tool and method which utilizes a combination of edge-applied force and vacuum force to remove the package from the socket. Most especially, the invention relates to such a tool and method in which the extraction force applied to the package scales upward proportionally to an increase in the number of connection pins of the package.
2. Description of the Prior Art
When an electronic package having, for example, several hundred connection pins extending from the package is in place in a socket on a printed circuit board with the pins held in their socket positions by friction, a considerable force is required to remove the package from the socket. A typical package of this type is referred to as a Pin Grid Array (PGA) package. The friction fit socket into which the pins of the PGA package are inserted is referred to as a non-Zero Insertion Force (ZIF) socket.
In conventional practice, when it is desired to remove a PGA package from its non-ZIF socket, a PGA extractor is used to grab the PGA package on its four edges to remove it from the socket. As package pin counts have increased to over 400, there has been an increased incidence of package breakage, due to the high stresses at the edges when sufficient force is applied to the edges of the package by the extractor to remove the package from the socket. The package breakage problem will get worse in the future, since the required extraction force scales as the number of pins, but the perimeter scales only as the square root of the number of pins.
Vacuum separation methods are used to separate boards comprising an electronic module in a Cray 2 computer. Vacuum grippers are used for many industrial and commercial applications, such as in the insertion and removal of automobile windshields. However, a vacuum applied force applied to an upper surface of an electronic package having a 100 mil (thousandths of an inch) grid of pins is insufficient for assuring removal of the pins from the socket. Assuming a hard vacuum of -14.7 psi, a lifting force of about 2.5 ounces per pin will be generated. However, depending on the particular non-ZIF socket a force of between about 2 ounces and a about 5 ounces per pin is required to assure package extraction.